1. Technical Field
Various embodiments relate to a semiconductor integrated circuit, and more particularly, to an internal voltage generation circuit.
2. Related Art
A semiconductor device generates and uses a voltage level for operation thereof based on an external voltage, that is, a voltage supplied from an external. The voltage generated by the semiconductor device is referred to an internal voltage. Further, a circuit, included in the semiconductor device, for generating the internal voltage is referred to as an internal voltage generation circuit.
FIG. 1 is a block diagram illustrating a conventional internal voltage generation circuit.
Referring to FIG. 1, the conventional internal voltage generation circuit includes a comparison unit 10, a pull-up driving unit 20, and a voltage division unit 30.
The comparison unit 10 compares a voltage level of a feedback voltage V_fb with that of a reference voltage Vref and generates a comparison signal Com_s.
The pull-up driving unit 20 drives a terminal for supplying an internal voltage V_int to be pulled up in response to the comparison signal Com_s.
The voltage division unit 30 divides the internal voltage V_int and provides the divided voltage as the feedback voltage V_fb that has a voltage level corresponding to the internal voltage V_int.
The conventional internal voltage generation circuit may maintain a voltage level of the internal voltage V_int at a target level by increasing the voltage level of the internal voltage V_int when the voltage level of the feedback voltage V_fb is lower than the voltage level of the reference voltage Vref.
The internal voltage V_int keeps the target level and is lowered below the target level when the internal voltage V_int is used by another internal circuit.
A semiconductor memory device as an example is described below with reference to FIG. 2.
The voltage level of the internal voltage V_int may be lowered below the target level when a command COMMAND is input to the semiconductor memory device. It is because the circuits, such as a receiver circuit for receiving the command COMMAND, a decoding circuit for decoding an output of the receiver circuit to decide what command is the command COMMAND and other internal circuits in the semiconductor memory device for performing a specific operation depending on the decoding result, consume the internal voltage V_int (i.e., a current flowing through the V_int terminal).
When the internal voltage V_int is lowered below the target level, the internal voltage generation circuit of FIG. 1 performs an operation to increase the voltage level of the internal voltage V_int that is currently below the target level. In the operation, an overshooting effect, which suggest that the voltage level of the internal voltage V_int is sharply increased to a voltage level that is higher than the target level, may occur.
When another operation (e.g., a data output operation DATA_out), which requires more power (i.e., the internal voltage V_int) than the operation corresponding to the command COMMAND, is performed in a state where the voltage level of the internal voltage V_int is higher than the target level due to the overshooting effect, the voltage level of the internal voltage V_int may be lowered more than the voltage level lowered due to the command COMMAND.
That is, when the overshooting effect occurs, the pull-up operation of the pull-up driving unit 20 is blocked, because the voltage level of the internal voltage V_int is higher than the target level due to the overshooting effect. Under such condition, if a large amount of the internal voltage V_int is rapidly consumed, it takes long time to recover the target level. Such a concern is caused by a low response speed of the comparison unit. That is, rapid consumption of an operation current in the overshooting period may cause the recovery time to be increased. Accordingly, it may be desirable to reduce the overshooting period.